Along with exhausting of Internet Protocol version 4 (IPv4) addresses, a Network Address Translation (NAT) technology is applied more and more widely. However, address resources are not allowed to be dynamically shared among Carrier Grade NAT (CGN) devices and NAT public network address pools are directly or indirectly configured on the devices, which may cause the phenomenon that some devices are in shortage of address pool resources but some devices are redundant in address pool resources.
For an operating company, the total IP addresses are limited, and regional and temporal unbalance may usually cause the phenomenon that IP addresses are constrained sometimes but redundant sometimes.
For example, both A and B have N IP addresses, the IP addresses of A are exhausted because of large-scale activities held in A, and an address utilization rate of B is sharply reduced to 50 percent because of population movement from B to A.